Upgrading main parity drive size and adding second parity disk- order?

[1812]

As title states, I'm upgrading my main parity drive from 2tb to 4, and adding a 2nd parity drive (4tb also) since I'm expanding from 6 disks to 15 as well (in later steps after preclearing.)

 

Would the "safest" way be to add the 2nd parity 4tb disk first, let it build, then when it is done, replace the primary 2tb?

 

 

 

[garycase]

I'd do it like this:

 

(a)  Do a parity check to confirm all is well before you start (this should always be the first step in making changes)

 

(b)  Replace the 2TB drive with a 4TB drive -- do NOT use the array while the rebuild is being done ... if anything was to go awry, you could always replace the 2TB parity drive and do a New Config with "Parity is already valid" and be back to where you started.

 

(c)  Do a parity check when it's done to confirm the rebuild went perfectly.

 

(d)  Add the 2nd parity drive.

 

(e)  Do yet-another parity check to confirm the parity sync for the 2nd drive also went well.

 

The extra parity checks (steps c & e) are optional, but I always confirm the results anytime I do a parity sync or a drive rebuild.

[BobPhoenix]

I have just added both parity drives as replacements to my existing parity drives.  It leaves you unprotected while it is building but if you only had 1 parity drive to start with you would be unprotected when you replace it.  I don't think you can add parity 2 > parity 1 first so I think you would have to be unprotected for that first build anyway so why not do both at the same time.  But correct me if I'm wrong.  Won't be the first time I've misunderstood something.

[garycase]

Actually Bob's idea is even better => just do a parity check to confirm all is okay;  then do a New Config with BOTH of your 4TB drives assigned as parity 1 & 2 and let it do a parity sync;  then do a parity check to confirm all was well ... and you're done .    If anything goes awry, you can do what I originally suggested -- just do another New Config with the original 2TB parity disk and the "Parity is already valid" box checked.

 

[JorgeB]

6 hours ago, BobPhoenix said:

I don't think you can add parity 2 > parity 1 first so I think you would have to be unprotected for that first build anyway so why not do both at the same time

 

You can add a larger parity2 first, then upgrade parity, it will take longer but array will always be protected.

[1812]

2 hours ago, johnnie.black said:

 

You can add a larger parity2 first, then upgrade parity, it will take longer but array will always be protected.

 

 

Thank everyone! I don't mind the extra time for the extra protection. 

[garycase]

True that adding the 2nd parity first and then upgrading the initial parity always leaves the array protected => but in effect the same thing is true if you simply do a New Config with two new parity disks PROVIDING you don't use the array at all (or more precisely don't write to it) during the parity sync ... since if anything was to go wrong during that process you can still do a New Config with the original parity disk and check the "Parity is already valid" box.